Visualize radioactive gamma rays & their absorption in materials using cycles
There are volumetric materials in Blender which can visualize such rays.

Blob with hole and radioactive stone inside (volume absorbtion with volume scatter):



You would "measure" the intensity with pixel value on the surface i guess

But I have an impression from your question that you would like to simulate the absorption or even measure it, you will not get any precise scientific result from Blender, only artistic. Blender does not work with real scientific units (except from dimensions) and its calculations take shortcuts to get better performance, its not precise.

That's why that specialized software is so expensive, it actually simulates it all.